The major objective of this study has been an investigation of vascular changes in experimental ocular inflammation, and what role these changes may play in recurrence of inflammation. Alterations in ocular vascular permeability, blood flow and structural integrity of blood vessels have been evaluated in different model systems, including the prolonged ocular vascular permeability resulting from the intravenous injection of bacterial endotoxin and the generalized shwartzman reaction, as well as the more transient alteration in ocular vascular permeability resulting from the intravenous injection of antigen-antibody complexes, and blood flow alterations in direct injection immunogenic uveitis. Studies in progress or contemplated for the coming year include: 1) A comparison of the ocular effects of intravenous bacterial endotoxin and antigen-antibody complexes regarding inhibition by anti-histamine and anti-serotonin agents and also the effects of steroid pretreatment. 2) The direct intraocular injection of 5 micrograms of Prostaglandin E sub 1 combined with the infusion of antigen-antibody complexes in an effort to localize immune inflammation and produce recurrent inflammation. 3) A study in previously inflamed eyes of prolonged vascular permeability.